The present invention relates to an arrangement at a portable electric apparatus comprising a main apparatus unit containing electronic equipment necessary therefore, and a detachable power source unit, the latter being disconnectably fixed to or in the apparatus unit, the arrangement being designed to allow ventilation of gaseous media in both directions inside and out from the apparatus unit as well as the power source unit to the atmosphere and vice versa due to changes in ambient temperature. More particularly, the present invention relates to a radio telephone having a removable rechargable battery pack
Previously known solutions for similar purposes are like the one according to EP A1 0 831 572, mainly filter members for suppressing the likelyhood that particles and other unwanted material enter the interior of a device.
Electronic equipment, normally consuming electric energy, stored in some kind of battery attached to or housed in the equipment, is normally effected by said energy consumption since the temperature of the battery rises as its energy is consumed. If the battery is rechargeable, which often or normally is the case, also the recharging generates a substantial amount of heat as well as sometimes the emission of hydrogen gas. Variation in temperature normally gives rise to vaporization and condensation, creating moisture almost everywhere. Such moisture and possibly emitted hydrogen gas in connection with mobile telephones, until now, has been tackled by natural leakage at joints and edges.
Electronic components of mobile telephones, like electronics overall, are normally not supposed to be exposed to moisture, since this enhances the risk for short circuiting as well as the risk of oxidation, which given time can destroy a component totally. These phenomena may become especially frequent when using mobile telephones in extreme environments, such as in the tropics, where its user sometimes may stay indoors in air-conditioned circumstances at 20xc2x0 C. and a humidity of 60% and at other times is staying outdoors at temperatures of maybe up to 70xc2x0 C. and humidities of maybe 90%. During such extreme conditions, the performance of almost any electronic devices or equipment may degenerate quickly.
It is therefore an object with the present invention to develop an arrangement for positively ventilating gas (mainly vaporized moisture in air and hydrogen gas) contained and/or generated inside a mobile telephone to the exterior thereof as well as providing means for submitting gas (air and no moisture) to the interior thereof in a controlled fashion, avoiding exposure of sensitive electronic equipment to moisture normally in the atmosphere.
Another object with the present invention is to provide a mobile telephone, which is water-protected, i.e., can withstand accidental exposure to water, but is not necessarily waterproof.
Another object is to provide a mobile telephone, which by the arrangement of channels for achieving a positive ventilation, also creates a pressure equalizer that equalizes possible internal positive or negative pressure that may result from such a water protection design. In water protected electronic equipment, the problem regarding moisture, whether condensated or vaporized and/or hydrogen gas, becomes worse in the absence of some kind of ventilation arrangement. The enclosed moisture, including possibly hydrogen gas, becomes more and more concentrated and may when released, for instance when charging a battery, oxidize into oxyhydrogen gas. If an ignition occurs, for instance a spark when releasing the battery, this resulting gas reacts according to the formula:
H2(g)+1/2O2(g)xe2x86x92H2O(1);xcex94Hxc2x0=xe2x88x92260 kJ,
a reaction which is more or less like an explosion.
According to the invention, means are provided for freely/positively [admitting] ventilating gaseous media, (e.g., air and hydrogen gas), in a controlled fashion via orifices in discrete components and/or compartments in the equipment. The means includes a channel or integrated channels encompassing the orifices in order to equalize air pressure in reach of the components or compartments. Ventilation of vaporized moisture, e.g., containing air and hydrogen gas, is performed in a controlled fashion via such channel(s) so that the moisture quickly evaporates without affecting surrounding equipment.
In a farther embodiment, the ends of the channel(s) are collected to a mutual outlet to the outside of the telephone. This outlet at its outer end is equipped with filtering media, preferably made from a material having a xe2x80x9cbreathingxe2x80x9d ability/function, like for instance GORE-TEX(copyright).
In a further embodiment, the channels are systematically arranged in for instance a honeycomb structure, regularly or irregularly spirally wound in one or more layers. This structure catches vaporized moisture or other gas at the spot(s) where they are the most concentrated.
The channels may also structurally strengthen a housing/shell for a mobile telephone. The channels are arranged in connection with a shell and thereby affects the moment of inertia thereof.
With the invention, a water-protected telephone may be provided without developing above- or sub-atmospheric pressure inside of the telephone.